1. Field of the Invention
The present invention relates to a method for manufacturing a color filter which is used for a display panel. Further, the present invention relates to a color filter which is manufactured by the above-described manufacturing method and an electronic appliance having the color filter.
2. Description of the Related Art
In recent years, demand of a display, especially, a color display has tended to increase due to the development of personal computers and the like. In the color display such as a liquid crystal display panel, the color filter for full color display is formed on a counter substrate. Polarizing plates are provided as a light shutter to an element substrate and the counter substrate, so that a full color image is displayed.
Here, the color filter of the liquid crystal display panel has colored layers of R (Red), G (Green) and B (Blue) and light-shielding partition walls (black matrixes) which are arranged in spaces between pixels. Light is transmitted through the colored layers to extract red light, green light and blue light. The partition walls (i.e. bank) of the color filter are generally formed with a metal film or an organic film containing black pigment. Each colored layer of this color filter is formed in a position corresponding to each pixel (hereinafter, referred to as a pixel region), whereby a color of light extracted from each pixel can be changed. Note that the position corresponding to the pixel refers to a position overlapping a pixel electrode.
An EL (electroluminescence) display device has three coloring methods. One is the arrangement of red, green, and blue emissive EL elements in matrix. A second method is the transmission of light emitted from a blue emissive EL element through a color conversion layer. The other is the use of the color filter in which coloring is performed by transmitting light emitted from a white emissive EL element through the color filter. The coloring method in which light emitted from the white emissive EL element is transmitted through the color filter is similar in principle to a coloring method of a liquid crystal display device using the color filter.
As a method for manufacturing such a color filter, a method has been investigated in which the colored layers corresponding to R (Red), G (Green) and B (Blue) are formed by an ink-jet method (see Patent Document 1: Japanese Published Patent Application No. S59-75205). Because a very high-resolution patterning of each colored layer is required for the color filter, the partition walls are provided onto the substrate to prevent color mixing between different pixel regions when the ink-jet method is applied. However, there has been a problem in that color filter materials frequently overflows the partition wall to result in the color mixing of the color filter materials. Therefore, as a correcting method of color mixing of the color filter, a correcting method with the use of a laser beam has been proposed (see Patent Document 2: Japanese Published Patent Application No. H3-274504). In addition, a method for preventing color mixing has been proposed in which wettability is controlled by surface treatment to avoid the spread of the color filter material to a different pixel region (see Patent Document 3: Japanese Published Patent Application No. 2006-162882).